Abstract: In this paper, a new concept, or virtual view point, is defined, and a new method for ray tracing buildings and environmental images is proposed, which can be used to generate realistic image including reflections and shadows of both buildings and environmental objects （e.g.trees, people, etc.）. Horizontal profiles and depth information of environmental images can be automatically extracted. The reflections and the shadows of environmental images can be achieved much realistically by means of the virtual view point. The new method can also simulate the reflections of buildings in puddles. It is shown that the image based and graphics based ray tracing techniques can generally meet requirements of architectural CAD and its realistic image generation.